It's probably out-of-plumb. Considering the folks that use it, though, it could very well have been shifted while in use.
As I suggested earlier, don't let the drywall fool you; this is in a rather high-abuse industrial location- and probably should have been done in a different style.
I took this pic as an example of a violation of NEC 314.21, which limits the gaps to the sides of the mud ring to 1/8".
If you saw the entire job site- trust me on this one- you would quickly realise that this is the least of his NEC and OSHA problems!
I won't trash this customer, however. I get called from time to time to fix things he THOUGHT he could do himself. He is learning that it's better to pay to have it done right the first time.